1. Field of the Invention
The present invention relates in general to sunroof structures of a motor vehicle, and more particularly, to sunroof structures of a canvas top type which uses a canvas as a folding top which is adapted to close an aperture formed in a roof of the vehicle.
2. Description of the Prior Art
Hitherto, various types of sunroof structures have been proposed and put into practical use particularly in the field of wheeled motor vehicles. Some of them are of a so-called "canvas top" type which uses a canvas as the folding top for closing the roof aperture of the vehicle. One of the sunroof structures of this type is disclosed in Japanese Utility Model First Provisional Publication No. 61-33721.
The sunroof structure of this publication comprises generally a folding canvas top carried on supporting bows, a pair of guide members extending along respective sides of the sunroof aperture to guide forward and rearward movements of the supporting bows, a front carry member connected to a front end of the canvas top and slidably guided by the guide members, a cable-type drive device for moving the front carry member forward and rearward upon operation thereof, and a manually operated handle for operating the drive device. A rear end of the canvas top is fixed to a rear end of the sunroof aperture.
When, opening the aperture, the manual handle is manipulated and, the front carry member is gradually moved rearward while forming several folds of the canvas top at a rear part of the same. When the manipulation of the handle stops, the rearward movement of the front carry member stops. Under this, due to the nature of a speed reduction mechanism employed in the sunroof structure, the front carry member is restrained at a position permitting the canvas top to assume a so-called "half-open restrained" position. When the manual handle is further manipulated, the front carry member is moved to its rearmost position allowing the canvas top to assume its full-open position.
However, due to its inherent construction, the conventional sunroof structure has the following drawbacks.
That is, since the folds of the canvas top, which are formed upon full-opening of the same, are inevitably placed at the rear portion of the sunroof aperture, the passengers on rear seats of the vehicle cannot enjoy a sufficiently large open space above them. In fact, under the full-open condition of the sunroof structure, the folds of the canvas top are placed over the rear seat passengers.
In order to solve this drawback, a measure has been proposed by the same applicants (which is disclosed in U.S. patent application No. 07/334,285 filed on Apr. 6, 1989) in which the opening movement of the canvas top is available from not only the front part thereof but also the rear part thereof. That is, in the measure proposed in the Application, there is employed a rear carry member which has a rear end of the canvas top secured thereto. The rear carry member is slidable along the paired guide members and detachably connected to the rear end of the sunroof aperture. Thus, if required, the rear carry member is detatched from the rear end of the aperture and pushed forward to a so-called "rear open position" providing a sufficiently wide open space above the rear seat passengers.
However, in the measure desclosed in the prior Application, there is no special means for assuredly holding the rear carry member at the rear open position.
Thus, when, with the sunroof structure assuming the rear-open condition and, the vehicle runs at high speed or subjected to rapid braking, the rear carry member is unexpectedly moved rearward or forward.